\documentstyle{article}
\textwidth 18cm
\textheight 23cm
\oddsidemargin -1cm
\topmargin 0cm
\parskip 0.15cm
\parindent 0pt
\small
\begin{document}
\def\izq#1{\hbox to -1.5pt{\hss#1}}
\arrayrulewidth 0.04cm
\begin{tabular}{|p{8.5cm}p{8.5cm}|} \hline
& \\
\multicolumn{2}{|c|}{\LARGE\bf THE\hspace*{1cm}STAR\hspace*{1cm}FORMATION\hspace*{1cm}NEWSLETTER} \\ [0.3cm]
\multicolumn{2}{|c|}{\large\em An electronic publication dedicated to early stellar evolution and molecular clouds} \\ [0.3cm]
{\hspace*{0.8cm} No. 33 --- 11 May 1995 } & \multicolumn{1}{r|}{Editor: Bo Reipurth (reipurth@eso.org)\hspace*{0.8cm}} \\ [-0.1cm]
& \\ \hline
\end{tabular}
\vspace*{0.3cm}
\begin{center}
{\Large\em Abstracts of recently accepted papers}
\end{center}
\vspace*{0.2cm}
%% Here you put between the brackets the title of your paper:
{\large\bf{ Vortices in Circumstellar Disks} }
%% Here comes the author(s) of the paper
{\bf{Fred C. Adams and Richard Watkins}}
%% Here, you write your institute name and the address
{Physics Department, University of Michigan, Ann Arbor, MI 48109, USA}
%% Within the following brackets you place your text:
{We discuss the physics of vortices in the circumstellar disks
associated with young stellar objects. We elucidate the basic physical
properties of these localized storm systems. In particular, we
consider point vortices, linear vortices, the effects of self-gravity,
magnetic fields, and nonlinear aspects of the problem.
We find that these vortices can exist in many different forms in the
disks of young stellar objects and may play a role in the formation
of binary companions and/or giant planets. Vortices may enhance giant
planet formation via gravitational instability by allowing dust grains
(heavy elements) to settle to the center on a short time scale; the
gravitational instability itself is also enhanced because the vortices
also create a larger local surface density in the disk. In addition,
vortices can enhance energy dissipation in disks and thereby affect
disk accretion. Finally, we consider the possibility that vortices
of this type exist in molecular clouds and in the disk of the galaxy
itself. On all of these size scales, vortices can produce
long-lived structures which may correspond to observed structures
in these systems. }
% Here you write which journal accepted your paper:
{ Accepted by The Astrophysical Journal }
\vspace*{0.3cm}
\newcommand{\tff}{\tau_{\rm ff}}
\newcommand{\rhot}{\widetilde{\rho}}
\newcommand{\Omreft}{\widetilde{\Omega}_{\rm c,ref}}
\newcommand{\nn}{n_{\rm n}}
\newcommand{\lreft}{\widetilde{\it l}_{\rm ref}}
\newcommand{\lr}{r_{\rm m}}
\newcommand{\tni}{\tau_{\rm ni}}
\newcommand{\tnit}{\widetilde{\tau}_{\rm ni,ref}}
\def\la{\mathrel{\hbox{\rlap{\hbox{\lower4pt\hbox{$\sim$}}}\hbox{$0)$ do not significantly affect the evolution;
magnetic braking remains effective during the quasistatic phase, and
ineffective during the (dynamic) collapse of the
magnetically and thermally supercritical core.
The initially very effective magnetic braking also means that the
solution is insensitive to values of $\Omreft$.
Different values of $\lreft$ yield qualitatively similar evolution, with
smaller cloud sizes leading to slightly smaller core sizes. Increasing
the value of $\tnit$ leads to more rapid evolution and larger, more
rapidly rotating cores. A smaller $k$ leads to relatively more
rapid evolution in the core and a better core-envelope separation.
We also give an analytical explanation of the
previously presented result, that the gravitational field acting on an
infalling mass shell in the central region
of a nonhomologously contracting thin disk increases as $1/\lr^3$, where
$\lr$ is the Lagrangian radius of the shell.}
{Accepted by The Astrophysical Journal, Oct 10 issue}
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{Studies of star formation in isolated small dark clouds. I.
A catalogue of southern Bok globules: optical and IRAS properties}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ T.L. Bourke,$^{1,2}$ A.R. Hyland$^{1,3,4}$ and G. Robinson$^{1}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^{1}$ { Department of Physics, University College, The
University of New South Wales, Australian Defence Force Academy,
Canberra, ACT 2600, Australia}\\
$^{2}$ { Present Address: Harvard-Smithsonian Center for
Astrophysics, 60 Garden St, MS 42, Cambridge, MA 02138, USA}\\
$^{3}$ { Faculty of Science, The University of New South Wales, Sydney,
NSW 2052, Australia}\\
$^{4}$ { Present Address: Office of the Vice Chancellor, Southern
Cross University, Lismore, NSW 2480, Australia}\\
{E-mail contact: tbourke@cfa.harvard.edu}
%% Within the following brackets you place your text:
{A comprehensive list of small southern molecular clouds (globules) has
been established from the survey of southern dark clouds of Hartley
et al. Only the densest globules, and those with diameters less
than 10 arcmin were included in the list. These are found to form an
entirely complementary sample to that of Clemens \& Barvainis in
the northern sky.
In this and the following paper a detailed study of the clouds has been
undertaken through an examination of their optical and IRAS
properties, and radio observations of ammonia. The aim of the study has
been to determine their physical characteristics, their role in the
formation of low mass stars, and the physical mechanism which either
triggers the star formation process, or stabilises the globules against
collapse.
The globules are predominantly elliptical. There is some evidence
that the apparent galactic
latitude distribution of our globules (as well as that of the
Clemens \& Barvainis sample) is
more highly concentrated towards the galactic plane than that of
the large molecular cloud complexes identified through CO surveys.
This suggests
that there are very few high latitude globules, or that selection
effects play a major role in defining the apparent distribution.
Of the 169 globules studied, 76 were found to have IRAS sources lying
toward them (totalling 83 sources). The IRAS sample is dominated by
cooler sources than the sample found to be associated with molecular
cloud cores by Beichman et al., and predominantly exhibit the
colours of embedded sources.}
% Here you write which journal accepted your paper, for example:
{ Accepted by M.N.R.A.S. }
{ A copy of this paper is available via the World Wide Web at:
http://cfa-www.harvard.edu/$\sim$bourke/papers.html }
\vspace{0.1cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Studies of star formation in isolated small dark clouds. II.
A southern ammonia survey}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ T.L. Bourke,$^{1,2}$ A.R. Hyland,$^{1,3,4}$ G. Robinson,$^{1}$
S.D. James$^{1}$ and C.M. Wright$^{1,5}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^{1}$ {Department of Physics, University College, The
University of New South Wales, Australian Defence Force Academy,
Canberra, ACT 2600, Australia}\\
$^{2}$ {Present Address: Harvard-Smithsonian Center for
Astrophysics, 60 Garden St, MS 42, Cambridge, MA 02138, USA}\\
$^{3}$ {Faculty of Science, The University of New South Wales, Sydney,
NSW 2052, Australia} \\
$^{4}$ {Present Address: Office of the Vice Chancellor, Southern Cross
University, Lismore, NSW 2480, Australia} \\
$^{5}$ {Max-Planck-Institut f\"{u}r Extraterrestrische
Physik, Postfach 1603, D-85740 Garching, Germany} \\
{E-mail contact: tbourke@cfa.harvard.edu}
%% Within the following brackets you place your text:
{A study of the set of small, southern molecular clouds (globules) compiled
by Bourke, Hyland \& Robinson has been undertaken, through radio
observations of ammonia using the Parkes 64 m telescope. The aims of
the study are to
determine the physical characteristics of the globules, their role in the
formation of
low mass stars, and the physical mechanism that triggers the star
formation process, or stabilizes the globules against collapse.
With these general aims in mind, the (1,1) and (2,2) inversion
transitions of ammonia were surveyed in order to determine the
densities, temperatures and masses of the globules.
Half of the globules were detected in ammonia, but only 6\%
of the detections were `strong' ($T_{a}^{*}$ $\geq$ 0.35 K). Comparing the
globule properties with those of Benson \& Myers for cores
within complexes, we find that the globules are less opaque and less
dense, and are less active sites of star formation. Other properties
are comparable. The Vela cometary globules were detected more readily
in ammonia than the more
isolated globules, and are more active star formation sites.
These results suggest that the dense core's
environment, in particular the presence of either a large external mass
or of a significant stellar wind,
plays an important role in initiating the star formation
process.}
% Here you write which journal accepted your paper, for example:
{ Accepted by M.N.R.A.S. }
{ A copy of this paper is available via the World Wide Web at:
http://cfa-www.harvard.edu/$\sim$bourke/papers.html}
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{Star Formation in the Gemini OB1 Molecular Cloud Complex}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ John M. Carpenter$^{1,2}$, Ronald L. Snell$^1$, \& F. Peter Schloerb$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{$^1$ Department of Physics and Astronomy, University of Massachusetts,
Amherst, MA 01003, USA}\\
{$^2$ Institute for Astronomy, Univ. of Hawaii, 2680 Woodlawn Drive,
Honolulu, HI 96822, USA; carp@galileo.ifa.hawaii.edu}
%% Within the following brackets you place your text:
{
We have conducted a study of the global star formation activity in the
Gem OB1 molecular cloud complex using a combination of molecular line,
near--infrared, and far--infrared data. A global survey for CS(J=2--1)
emission yielded 11 cores with masses $\ge$ 100~M$_\odot$. These cores
are typically elongated along arcs and filaments previously found in
a large scale $^{12}$CO and $^{13}$CO survey. Based on the morphology of
the cores,
the association of some filaments with optical HII regions, and comparison
of the observations with models with expanding HII regions, we suggest
that these massive cores have formed primarily in swept up shells of
molecular gas. At least 8 and possibly 10 of the 11 cores are associated
with star formation as traced by the distribution of IRAS point sources,
and the 3 cores contained in our near--infrared imaging survey each
contain a cluster of stars. The
high frequency of star formation associated with the cores suggests that
star formation in massive dense cores begins soon after the core is formed,
and that new cores must be continually formed if star formation is to
continue in the Gem OB1 complex. A systematic survey in CS of 58 IRAS sources
with far--infrared colors characteristic of young stellar objects indicated
that the more luminous IRAS sources tend to be associated with more massive
cores. This correlation suggests that more massive cores generally form
massive stars, although we cannot determine from these data if this is an
environmental or
statistical effect. Our near--infrared and CS results suggest that
dynamical evolution of the clusters and destruction of the cores are
important effects to consider when contrasting the properties of different
regions. A qualitative model for the Gem OB1 complex is proposed to explain
these observations in which the primary mechanism for the formation of the
massive dense cores is through the external compression of the molecular
gas. The dense cores will generally form clusters of stars that rapidly
disperse after the dense core is dissipated. The continual production of
dense cores is provided for by the constant interactions of the molecular
gas with energetic phenomena in the immediate environment.}
{ Accepted by the Astrophysical Journal }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Observation of Infrared and Radio Lines of Molecules \
toward GL 2591 and Comparison to Physical and Chemical Models}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ John S. Carr$^1$, Neal J. Evans II$^2$ \ John H. Lacy$^2$ and Shudong Zhou$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, The Ohio State University, Columbus, Ohio
43210-1106, USA} \\
$^2$ {Department of Astronomy, The University of Texas at Austin, Austin,
Texas 78712-1083, USA} \\
$^3$ {Astronomy Department, The University of Illinois, Urbana, Illinoi 61801 \
and Institute of Astronomy and Astrophysics, Academia Sinica, P. O. Box
1-87, Nankang, Taipei, Taiwan, 115, R. C. C. }
{E-mail contact: nje@astro.as.utexas.edu}
%% Within the following brackets you place your text:
{We have observed rovibrational transitions of C$_2$H$_2$ and HCN near 13
$\mu$m in absorption against GL2591. We have marginally detected
NH$_3$ and set upper limits on rovibrational lines of
CH$_4$, CS, SO, and SiO. We have also observed rotational
transitions at 0.6--3 mm of CS, HCN, H$_2$CO, and HCO$^+$.
The rovibrational data were
analyzed in comparison to the absorption line analysis of CO by
Mitchell et al. (1989). Our data are consistent with the C$_2$H$_2$
and HCN absorption arising in the same warm (200 K) and hot (1010 K)
components seen in CO, but we see little evidence for the cold
(38 K) component seen in CO. The results can be explained by a
model in which early-time gas-phase abundances are preserved on grain
mantles and later released at high temperature. Analysis of the
rotational lines indicates that these do not arise from the
same gas as the rovibrational lines. Comparison of the two data
sets shows that the rovibrational absorption of HCN must come from
a region with a small angular extent (less than about 2--3 arcsec, or about
2000--3000 AU at a distance of 1 kpc) and a much higher (factor of 400)
abundance. The rovibrational lines from higher
J states (J about 20) indicate that the hot HCN deviates from LTE.
A good fit is obtained for a density of about $3 \times 10^7$ cm$^{-3}$.
Analysis of the rotational lines, which arise in the extended cloud
around the source, shows that no single-density model can explain
all the data. Models with density and temperature gradients do much
better; in particular models with $n(r) \propto r^{-\alpha}$, with
$\alpha = 1.5$, can reproduce the observed pattern of emission
line strengths. Models with $\alpha = 1.0$ or 2.0 are less
satisfactory.
These models predict densities of $3 \times 10^7$ cm$^{-3}$ at
radii slightly smaller than, but similar to, the upper limits
on the size derived above.
The temperatures of the gas seen in the rovibrational lines
are clearly higher than predicted from a similar extension of the
temperature law, suggesting other sources of heating.
Comparison of the radio and infrared data indicate that the
line of sight to the infrared source has an unusually low
column density.}
{ Accepted by Astrophys. J. }
\vspace*{0.5cm}
{\large\bf{H$_2$O masers without associated diffuse H\,{\sc ii} regions: an earlier evolutionary phase?}}
{\bf{Claudio Codella$^{1}$, Marcello Felli$^{2}$}}
$^1$ {Dipartimento di Astronomia e Scienza dello Spazio,
Universit\`a di Firenze, Largo E. Fermi 5, 50125 Firenze,
Italy} \\
$^2$ {Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze,
Italy}
{In apparent contrast with the common belief that galactic H$_2$O masers are
always found associated with H\,{\sc ii} regions,
the majority (80\%) of H$_2$O masers
are without diffuse H\,{\sc ii} regions.
The aim of this work is to confirm the lack of diffuse ionized gas
around these masers, and
to see if these sources
represent a homogeneous sub-class in an earlier evolutionary
phase in which a
diffuse H\,{\sc ii} region
has not yet formed.
We present the results of a search for H89$\alpha$ (3 cm)
hydrogen recombination line towards a sub-sample of 60 of these
masers.
The detection rate is very low: only 2 sources (3\%) show recombination
line emission.
In order to explain this low detection rate,
we have examined possible selection effects, such as
sensitivity of the recombination line observations,
or lack of ionized gas because of the low luminosity of the associated star.
Although both effects can play some role, by no means
can they account for the large number of masers without associated
diffuse H\,{\sc ii} regions.
The most probable answer is that
masers form very early, much before the formation of a diffuse
H\,{\sc ii} region, and spend most of their life in this
evolutionary stage.
The 20\% positional agreement between H\,{\sc ii} regions and water masers
found in low resolution (arcmin) surveys may indicate that maser
emission continues for a fraction of the main-sequence
life-time of the newly formed star.
Alternatively (and more probably), this coincidence may reflect that more
than one star-formation event (i.e. the formation of a new maser)
occurs in a stellar cluster and that these are spread
over an extended period, longer than that required
by the first massive stars of the cluster to develop their own
H\,{\sc ii} regions.}
{Accepted by Astronomy and Astrophysics}
\vspace*{0.5cm}
{\large\bf{IRAS selected Galactic star-forming regions II:
water maser detections in the extended sample}}
{\bf{Claudio Codella$^{1}$, Giorgio G.C. Palumbo$^{2,6}$, Giovanni Pareschi$^{3}$,
Flavio Scappini$^{4}$, Paola Caselli$^{5}$, Maria R. Attolini$^{6}$}}
$^1$ {Dipartimento di Astronomia e Scienza dello Spazio,
Universit\`a di Firenze, Largo E. Fermi 5, 50125 Firenze,
Italy} \\
$^2$ {Dipartimento di Astronomia, Universit\`a di Bologna, Via Zamboni 33, 40126 Bologna,
Italy} \\
$^3$ {Dipartimento di Fisica, Universit\`a di Ferrara, Via Paradiso 12, 44100 Ferrara, Italy} \\
$^4$ {Istituto di Spettroscopia Molecolare del C.N.R., Via Gobetti 101, 40129 Bologna, Italy} \\
$^5$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
Cambridge, MA 02138, USA} \\
$^6$ {Istituto di Tecnologia e Studio delle Radiazioni Extraterrestri del C.N.R., Via Gobetti 101,
40129 Bologna, Italy}
{The results of the analysis of the occurrence of 22.2 GHz H$_{2}$O maser emission
in a sample of 1409 IRAS sources north of declination --30$^o$
associated with star-forming regions are presented.
Our sample contains all the IRAS sources which satisfy Emerson criteria
to select molecular cores associated with the earliest evolutionary stages of the
star-forming process. In a previous paper we have reported the results of
the observations of about one third of the sample. In the present paper the
observations of the remaining IRAS sources are presented: 18 of them
are newly detected maser sources.
The results show that 20\% of all IRAS sources which satisfy also the
Wood and Churchwell criteria have water masers. This is in accord
with the assumption that these criteria can select objects connected
with the early phases of the evolution of high-mass
star-forming regions. Moreover, about one third of the whole sample
selected according to Emerson criteria contains
IRAS sources which are not associated with massive star-forming process, but
probably with molecular cores in low-mass star-forming regions.}
{Accepted by Monthly Notices of the Royal Astronomical Society}
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{High-Resolution Far-Infrared Observations of DR 21}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Cecilia Colom\'e$^1$, Paul M. Harvey$^1$, Daniel F. Lester$^1$,
Murray F. Campbell$^2$ \ and Harold M. Butner$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, C1400, University of Texas at Austin,
Robert Lee Moore Hall, Austin, TX 78712, USA} \\
$^2$ { Department of Physics and Astronomy, Colby College, Waterville,
ME 04901, USA
} \\
$^3$ {Carnegie Institute of Washington, Department of Terrestial Magnetism,
Washington, DC 20015, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: cc@astro.as.utexas.edu}
%% Within the following brackets you place your text:
{We present new, high angular resolution two-color maps of the compact H II
region DR 21 at 50 $\mu$m and 100 $\mu$m made with the 0.91 m telescope
of NASA's Kuiper Airborne Observatory (KAO). From the maps we estimate the
total fluxes of DR 21 at 50 $\mu$m and 100 $\mu$m to be 1.5 $\times 10^4$ Jy
and 3.8 $\times 10^4$ Jy, respectively.
1. A homogenous plane-parallel slab model (Model I) is assumed in order to
derive dust temperatures and optical depths. This model implies that the
dust in DR 21 has relatively small optical depths at 100 $\mu$m
($\tau_{100} \sim$ 0.1) and its temperature ranges from less than 20 K
to $\sim$ 50 K.
2. A second model is also presented (Model II): a spherical symmetric dust
cloud surrounding an O6 star. We used the radiation transfer code developed
by Egan, Leung \& Spagna (1988). Our selection criteria for the best fit
were based on the best match for both the energy distribution in the
50-1300 $\mu$m range and the 100 $\mu$m source profile. Assuming the dust
properties reported by Mathis, Mezger, \& Panagia (1983), and using a
mixture of graphite (50\% by number) and silicate (50\% by number), the
best fit to the observations in our modeling with this approach is a
spherical dust cloud described by anouter radius of 2.0 pc, an inner
radius of 0.1 pc, and a CONSTANT dust density distribution.
Although this model provides a reasonable fit to the 50-1300 $\mu$m flux
densities and a marginal fit to the 100 $\mu$m profile, the predicted FWHM
profiles at 800 and 1100 $\mu$m are much broader than those observed with
high angular resolution (15$''$ and 19$''$ beams, respectively) as reported
in the available literature}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{The Distribution of Warm Dust in the Star-Forming Region
Cepheus A: Infrared Constraints}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Cecilia Colom\'e$^1$ \ and Paul M. Harvey$^1$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Dept. of Astronomy, The University of Texas at Austin,
Robert Lee Moore Hall, Austin TX 78712, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: cc@astro.as.utexas.edu}
%% Within the following brackets you place your text:
{We have obtained new, high angular
resolution far-infrared (FIR) maps (at 50 and 100 $\mu$m) of the star-forming
region Cepheus A and polarimetric images (1.65 and 2.2 $\mu$m) of the
reflection nebulosity, IRS 6, associated with this young stellar object.
From our FIR maps we calculate the dust temperature and optical depth
at 100 $\mu$m. Cepheus A has moderate optical depths ($\tau_{100}$ $\leq$ 0.3)
and its dust temperature ranges from 30 to 50 K. The two-
dimensional map of the 100 $\mu$m optical depth indicates that there
is a region of lower dust column density near the peak of the FIR
emission. A radiative transfer code was used to model the available
photometry and the FIR data of Cepheus A. A spherical dust cloud with
a central young star was assumed, and the input parameters in this
model were varied in order to reproduce: (a) the spectral energy
distribution and (b) the high angular resolution profiles at FIR
wavelengths. The model that gives the best fit to the observations
requires a dust cloud of the following characteristics:
$R_{outer}$=0.5 pc, $R_{inner}$=0.07 pc, $\tau_{100}$=0.15, $\alpha$=1.5,
where $R_{outer}$, $R_{inner}$, $\tau_{100}$ and $\alpha$ are the
outer radius, inner radius, optical depth at 100 $\mu$m and exponent of the
power law in the emitting-dust density gradient: $n_d(r)=n_0(r/r_0)^{-\alpha}$.
The inner radius used in this model ($R_{inner}$=0.07 pc) is similar in
size to the $``$cavity" derived from the two-dimensional map of the dust
optical depth at 100 $\mu$m. For small distances (r $\leq$ 0.15 pc) from
the infrared peak a second density gradient is derived from the distribution
of the near-infrared (NIR) polarization. In this inner region of the dust
cloud, the NIR polarization indicates that the density of the scattering
dust should remain constant or increase slightly with distance. Our results
are consistent with current star formation theories: a young stellar object
surrounded by an infalling envelope with a characteritic density
distribution of :$n_d(r) \propto r^{-1.5}$, a circumstellar disk, and a cavity
($R_{inner} \sim$ 0.07 pc) in which $n_d$ is constant, created by the
dispersal of the initial dust cloud by a strong stellar wind.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{Near-infrared imaging in H$_2$ of molecular (CO)
outflows from young stars}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{C.J. Davis$^1$ and J. Eisl\"offel$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl 17, D-69117
Heidelberg, Federal Republic of Germany} \\
$^2$ {Laboratoire d'Astrophysique, Observatoire de Grenoble, Universit\'e Joseph Fourier, B.P. 53X, F-38041 Grenoble Cedex, France}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: davis@mpia-hd.mpg.de}
%% Within the following brackets you place your text:
{In an attempt to identify the molecular shocks associated with the
acceleration of ambient gas by collimated outflows from young stars, we
have imaged a number of known molecular (CO) outflows in H$_2$ v=1-0\,S(1)
and wide-band K. H$_2$ line emission is detected in all six sources:
\begin{enumerate}
\item{In the L\,1157, VLA\,1623 and NGC\,6334I outflows, bow-shaped H$_2$
features are observed coincident with or just ahead of (downwind of)
peaks in the CO outflow maps.}
\item{In NGC\,2264G, as well as a compact group
of H$_2$ knots coincident with the blue-shifted CO peak, we see an
extended H$_2$ filament that traces the northern edge of the
red-shifted CO flow.}
\item{In the L\,1641N and Haro\,4-255 molecular outflows
we see a close correlation between H$_2$ line emission features
and peaks in the CO outflow maps}.
\end{enumerate}
In each outflow system, the H$_2$ probably results from shocks
associated with the interaction of the flow with the ambient, molecular
gas. A comparison of the H$_2$ data with CO outflow maps strongly
suggests that {\em ``prompt entrainment'' near the head of a jet is the
dominant mechanism for producing the CO outflows in at least some of
these sources.} We are also able to account for the ratios of observed
radiated energy (derived from H$_2$ v=1-0\,S(1) flux measurements) to
mechanical power in the CO outflows in at least half of the outflows
with a very simple, strong, radiative shock model.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. Astrophys. }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{The S 269 stellar cluster}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ C. Eiroa$^1$, M. M. Casali$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Dpto Fisica Teorica C-XI, Facultad de Ciencias, Universidad
Autonoma de Madrid. Cantoblanco. E-28049 Madrid, Spain.
e-mail: carlos@astro1.ft.uam.es} \\
$^2$ {Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, United
Kingdom. e-mail:mmc@star.roe.ac.uk}
%% Within the following brackets you place your text:
{We present the results of an imaging observational study of the
young cluster associated wtih the HII region S 269. Images of the region
have been carried out at optical (RI and emission line) and near-IR (JHK and
narrow L) wavelengths. The I image detects nearly 300 sources with a remarkable
clustering towards the western lobe of the HII region and the surroundings
of the ionizing stars. The K image (extending to a more reduced field) detects
100 sources again showing a clear clustering. 79 objects are identified as
members of the S 269 young cluster, the rest of the objects remaining
unidentified. Our results suggest that the stars detected in S 269 could
form either a massive BA stellar cluster suffering high extinction, or a
PMS low-mass stellar cluster in which a few massive stars have formed
already. In addition, we briefly discuss the apparent magnitude
distribution}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy and Astrophysics }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{
Sequential Star Formation in OB Associations: The Role of
Molecular Cloud Turbulence}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Bruce G. Elmegreen$^1$,
Toshiya Kimura$^2$ \ and Makoto Tosa$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$
{IBM Research Division, T.J. Watson Research Center,
P.O. Box 218, Yorktown Heights, NY 10598, USA}\\
$^2${National Aerospace Laboratory,
Computational Sciences Division,
7-44-1, Jindaijihigashi-machi, Chofu, Tokyo, 182, Japan}\\
$^3${Astronomical Institute, Tohoku University,
Sendai 980-77, Japan}
%% Within the following brackets you place your text:
{Numerical simulations of shock propagation into a 2-dimensional,
clumpy, turbulent cloud suggest that the average shock speed,
$v_{\rm s}$, approximately
equals the square root of the ratio of the external pressure
to the average preshock density, $\rho_0$, and that the average
shocked layer density, $\rho_{\rm s}$, approximately
equals the product of
$\rho_0$ and the square of the velocity ratio, $v_{\rm s}/v_{\rm turb}$,
for postshock rms turbulent speed $v_{\rm turb}$.
A comparison is made between seven theoretical
formulations for the shock speed; all differ slightly from
each other and from the measured shock speed, but usually not by
more than a factor of 1.5. The maximum postshock
density is much larger than the average postshock density
because of the clumpy postshock structure; the maximum is comparable
to $\rho_0 (v_{\rm s}/v_{\rm th})^2$ for postshock thermal
speed $v_{\rm th}$. These relations are useful for the
interpretation of
forced cloud motions and shock speeds in turbulent molecular clouds
near HII regions.
Preshock clumps form self-consistently by supersonic turbulence
compression in the initial preshock gas. As the shock moves into the
cloud, these clumps are squeezed and collected into the compressed
layer, and they merge into a few massive, clumpy, postshock cores.
The cores should produce bright rims in a real HII region
because they protrude slightly into the ionized gas.
The escape velocity in a typical model postshock core is
larger than both the internal core velocity dispersion and the shock
speed. Such a core would collapse gravitationally
and ultimately form a star cluster. Stars could also form earlier
when the preshock turbulent clumps collide with each other
inside the postshock layer, or when
the clumps are squeezed by the high pressure shock.
Thus there could be an
age spread inside the triggered cluster equal to the entire age of the
shock, although most of the stars will form when the massive
postshock cores collapse.
The separation between OB association subgroups should be
related to the time for the embedded cluster to grow
to such a large mass that the stellar pressures inside
the core disperse the gas and halt further star formation.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophys. J. }
\vspace*{0.5cm}
{\large\bf{Photometric observations of pre-main sequence objects}}
{\bf{M. Fern\'andez$^{1,2}$}}
$^1$ Instituto de Astronom\'{\i}a, UNAM, Apdo. 70-264, 04510
M\'exico D.F., M\'exico \\
$^2$ Dpto. F\'{\i}sica Te\'orica, C-XI, Univ.Aut\'onoma
Madrid, Ciudad Univ. Cantoblanco, E-28049 Madrid,
Spain
{E-mail contact: matilde@astroscu.unam.mx}
{ We present the observational data
of a photometric monitoring of 24 pre-main sequence
objects: T Tauri stars, Ae/Be Herbig stars and some unclassified objects.
Observations were carried out from July 1988 to August 1992, using the
UBV(RI)$_c$ system.
Variability with time scales from days to years and amplitudes in the V band
larger than 0.1 mag is found for a part of this sample.
The ana\-ly\-sis of the possible causes of this variability
are discussed in separate papers (Fern\'andez \& Eiroa
1995a,b).}
{ Accepted by Astron. Astrophys. Suppl.}
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{ Speckle Imaging Measurements of the Relative Tangential Velocities of
the Components of T Tauri Binary Stars}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ A. M. Ghez$^{1}$, A. J. Weinberger$^2$, G. Neugebauer$^2$,
K. Matthews$^2$, and D. W. McCarthy, Jr.$^3$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, University of California, Los
Angeles, CA 90095-1562, USA, ghez@urania.astro.ucla.edu} \\
$^2$ {California Institute of Technology 320-47, Pasadena, CA 91125, USA} \\
$^3$ {Steward Observatory, University of Arizona, Tucson, AZ 85721, USA}
%% Within the following brackets you place your text:
{Over a five year period, we have used speckle imaging to monitor 20 T Tauri
binary stars with separations ranging from 0.$''$09 to 1$''$ (13 to 140 AU).
This project is aimed at detecting the relative motion of the
component stars to ascertain whether or not the observed companions
(1) are stellar in nature, as opposed to being HH objects, and (2) are
gravitationally bound to the primary stars.
These observations demonstrate that speckle imaging measurements of close binary
stars'
separations can be made with an accuracy of a few milliarcseconds.
The majority of the observed systems show significant relative velocities
which (1) are not consistent with the motion expected for HH objects, (2)
are greater than the velocity dispersion of these star forming regions and
thus are not the result of differential proper motion, and (3)
are consistent with orbital motion. This is the first demonstration
that these systems are physically bound. Furthermore, these relative
velocity measurements provide dynamical evidence that the average total
mass of these T Tauri binary stars systems is $\approx$1.7 $M_{\odot}$.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomical Journal }
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{The $\beta$ Pictoris phenomenon among young stars.
II. UV observations of the Herbig Ae star UX Orionis}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ C.A. Grady $^1$, M.R. P\'erez$^1$, P.S. Th\'e$^2$,
V.P. Grinin$^3$, D. de Winter$^2$, S.B. Johnson$^4$,
A. Talavera$^5$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Applied Research Corp., 8201 Corporate Dr., Suite 1120, Landover,
MD 20785, USA}\\
$^2$ {Astronomical Institute ``Anton Pannekoek'', University of Amsterdam,
Kruislaan 403, 1098 SJ Amsterdam, The Netherlands}\\
$^3$ {Crimean Astrophysical Observatory, P/O Nauchny, Crimea,
334413, Ukraine}\\
$^4$ {Idaho State University, Pocatello, ID 83209, USA}\\
$^5$ {ESA IUE Observatory, Vilspa, P.O. Box 50727, E-28080 Madrid, Spain}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: grady@fosvax.arclch.com}
%% Within the following brackets you place your text:
{
IUE spectra of the Herbig Ae star UX Ori reveal the
presence of large amplitude light and color changes, which are an extension
to shorter wavelengths of the \char'134 blueing" effect seen in the optical.
At optical maximum the UV spectrum of UX Ori is dominated by heavy line
blanketing from accreting circumstellar gas with velocities as high as +200
km s$^{-1}$. At minimum light, prominent mid-UV emission from Fe II and Mg II is
present, and the overall spectrum closely resembles spectra of more
heavily embedded Herbig Ae stars.
Comparison of the UV and optical data for UX Ori suggest that single
parameter ISM-like extinction curves do not fit the observed data near
optical maximum light, when contamination by scattered circumstellar dust
is minimized. The best fit to the UV color-magnitude diagram is for
circumstellar
extinction dominated by silicate grains with a$_{min}\geq$0.15 $\mu$m,
and with a power law distribution $n(a)=a^{-2}$, suggesting that both the
particle size distribution and grain chemistry in the inner disk have
evolved considerably from those characteristic of molecular clouds in the
2-3 Myr since the formation of UX Ori.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy \& Astrophysics}
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{The ratio $N$(CO)/$E(J-K)$ in local molecular clouds}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ P. Harjunp\"a\"a and K. Mattila}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Observatory, P.O. Box 14, SF-00014 University of Helsinki, Finland}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: harjunpaa@cc.helsinki.fi}
%% Within the following brackets you place your text:
{We have investigated the ratio of carbon monoxide column density to colour
excess $E(J-K)$ of background field stars in the direction of three different
local clouds: the Coalsack, Chamaeleon~I (Cha~I) and R~Coronae Australis
(R~CrA). For these dark clouds a uniform set of colour excess values towards
highly reddened background stars is available from the literature based on
near-infrared photometry data. Using the 15-m Swedish-ESO Submillimeter
Telescope (SEST), we have observed towards these background stars the
$^{12}$CO, $^{13}$CO and C$^{18}$O $J=1-0$ emission lines and, in a few
selected directions, the $J=1-0$ transition of C$^{17}$O. We have also derived
the $N$(CO)/$A_{\rm V}$ ratio and, based on a range of assumed
gas-to-dust-ratios, the $N$(CO)/$N$(H$_{2}$) ratio. We find that the $N$(CO) to
$E(J-K)$ ratio varies from cloud to cloud: it is a factor of $\sim$~2 larger in
Cha~I and R~CrA than in the Coalsack. Our results can be interpreted in two
alternative ways: firstly that the $N$(CO)/$N$(H$_{2}$) ratio is higher in
active star forming regions (Cha~I, R~CrA, and L~1641) than in more quiescent
regions without star formation (Coalsack) and secondly that the
ratio $N$(H$_{2}$)/$E(J-K)$ changes from cloud to cloud and is higher in
active star forming regions than in quiescent clouds.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy and Astrophysics }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Disk Accretion and Mass Loss From Young Stars}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Patrick Hartigan$^1$, Suzan Edwards$^2$ \ and Louma Ghandour$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Space Physics and Astronomy, PO Box 1892, Rice
University, Houston TX 77251, USA} \\
$^2$ {Five College Astronomy Department, Smith College, Clark Science Center,
Northampton, MA 01063, USA} \\
$^3$ {Five College Astronomy Department, University of Massachusetts
Amherst, MA 01003, USA}
%% Within the following brackets you place your text:
{In this paper we investigate how mass outflows from young stars relate to circumstellar disks
by analyzing spectroscopic data of 42 T Tauri stars that span a broad range of infrared excesses.
We measure the optical excess continuum (veiling) in each star from high-resolution 4-m spectra,
and extract forbidden line profiles uncontaminated by terrestrial night sky emission,
photospheric absorption lines and telluric absorption lines.
The veiling fluxes combined with existing infrared photometry allow us to estimate
reddenings and stellar luminosities for the first time for heavily
veiled stars. The new estimates of the stellar luminosities of
these objects indicate that the stars with the highest accretion rates are the youngest in the sample.
There is a one-to-one correspondence between forbidden line emission,
veiling, and near-infrared color excess among the stars in our sample;
all disks around young stars which are both optically
thick and extend inward to within a few stellar radii of the stellar
surface are, in fact, accretion disks, and have forbidden line emission.
Residual forbidden line profiles of [O~I] $\lambda 6300$, [O~I] $\lambda 5577$,
[S~II] $\lambda 6731$, and [N~II] $\lambda 6583$, represent a range of critical densities
from $10^{4}$ to $10^{8}$ cm$^{-3}$. We have determined luminosities and line ratios
for the two distinct velocity components in each of these forbidden lines.
The high velocity component resembles a dense stellar jet, but
requires more than a single shock to account for the observed line ratios.
Luminosities of the high velocity component indicate mass loss rates of
$\sim$ $10^{-8} - 10^{-10}$ M$_{\odot}$ yr$^{-1}$ for most stars, and
disk accretion rates derived from the veiling fluxes are $\sim$
$10^{-6} - 10^{-8}$ M$_{\odot}$ yr$^{-1}$. The mass outflow rates and mass accretion rates are
correlated. The ratio of mass outflow rate to the mass accretion rate depends upon how the
forbidden line luminosities are interpreted, but is probably $\sim$ 0.01 for most classical T~Tauri stars.
The low velocity component originates in a region of higher density than the high velocity component,
and is characterized by a small negative radial
velocity ($\sim - 5$ km s$^{-1}$), possibly associated with a disk wind or magnetic accretion columns.
The velocity shifts are largest for forbidden lines with the lowest
critical density, suggesting that the low velocity component accelerates away from the
surface of the disk. If the low velocity component arises from the surface of
a disk in Keplerian rotation, then the observed
profiles imply that the surface brightness of the disk decreases as $\sim$ r$^{-2.2}$.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by the Astrophysical Journal }
This paper is available as a compressed postscript file from the Dept.~of Space Physics and
Astronomy Preprint Server. The WWW address is {\bf http://spacsun.rice.edu}
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Sulphur monoxide in the galactic cirrus }}
%
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Andreas Heithausen$^1$, Uwe Corneliussen$^1$, and Volkmar
Gro\ss\-mann$^2$}}
%
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {I. Physikalisches Institut der Universit\"at zu K\"oln,
Z\"ulpicher Stra\ss e 77, 50937 K\"oln, Federal Republic of Germany}\\
$^2$ {Institut f\"ur Astronomie und Astrophysik - Astronomie,
Universit\"at T\"ubingen, Wald\-h\"auser Str. 64,
72076 T\"ubingen, Federal Republic of Germany}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: heithausen@ph1.uni-koeln.de}
%% Within the following brackets you place your text:
{We report the discovery of the SO ($N_J=1_0\to0_1$) line near 30 GHz
with the MPIfR 100 m telescope in two dense cores located in the galactic
cirrus clouds MCLD123.5+24.9 and MCLD126.6+24.5 The emission is quite intense
and extends over several arcmin. Since the SO line is most likely optically
thick, we can only derive a lower limit for the cloud averaged column densities
$N$(SO$)>10^{13}$cm$^{-2}$. Both cores have also been mapped in the
$^{13}$CO $(J=3\to2)$ transition
using the KOSMA 3 m telescope. Applying an escape propability model
to match the observed line strength of this transition and of already published
$(J=1\to0)$ data gives column densities in the range
2.0~10$^{15}$ cm$^{-2}\le N(^{13}$CO$)\le 6.0~10^{15}$ cm$^{-2}$
and volume densities in the range of
0.5~10$^4$ cm$^{-3}\le n($H$_2)\le 2.5~10^4$ cm$^{-3}$.
Comparison of the SO column densities with the H$_2$ column densities
derived from these $^{13}$CO or already published C$^{18}$O
column densities gives a lower limit for the fractional abundance of
$X$(SO$)>4~10^{-9}$. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. \& Astrophys. }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Nonaxisymmetric Secular Instabilites Driven by Star/Disk Coupling}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ James N. Imamura$^1$, Joseph Toman$^1$, Richard H. Durisen$2,3$, Brian K. Pickett$^2$, and Shelby Yang$^2,4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute of Theoretical Science and Department of Physics,
University of Oregon, Eugene, OR 97403, USA} \\
$^2$ {Department of Astronomy, Indiana University, Bloomington, IN
47405, USA} \\
$^3$ {Max Planck Institute for Extraterrestrial Physics, 85740 Garching, Germany}
$^4$ {Center for Innovative Computing Applications, Indiana
University, Bloomington, IN 47405, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: imamura@herb.uoregon.edu}
%% Within the following brackets you place your text:
{We determine conditions for the onset of nonaxisymmetric secular
instabilities in polytropes with a wide range of angular momentum distributions using Lagrangian techniques, and we then calculate the growth rate of such
instabilities when driven by the coupling of the perturbed star to a
circumstellar disk. We use Lagrangian replacement vectors with azimuthal
coordinate. The onset of secular instability in terms of the quantity
$T/|W|$, the ratio of rotational kinetic energy to gravitational potential
energy, is affected by both the compressibility and the angular momentum
distribution of the polytrope. The largest effects arise as the angular
momentum distribution is varied. For polytropic index $n$ = 3/2, the onset
of secular instability for the $m$ = 2 mode (the bar mode), as determined by
its neutral point, shifts from $T/|W|$ = 0.141 to 0.093, while the $m$ = 5
mode neutral point shifts from $T/|W|$ = 0.088 to 0.031 over the range of
angular momentum distributions we consider. The smallest critical
$T/|W|$-values occur for the angular momentum distribution of a Maclaurin
spheroid, as the polytropic index $n$ is increased from 3/2 to 5/2, the
neutral point for $m$ =2 shifts from $T/|W|$ = 0.069 to 0.78. The neutral
points for the $m$ = 2 and 5 for the Maclaurin sequence ($n$ = 0) are 0.127
and 0.0629, respectively. As the angular momentum distribution becomes more
peaked toward the equatorial radius of the polytropes, the critical
$T/|W|$-values generally become less sensitive to the compressibility of the
polytrope.
Star/disk coupling can drive the secular instability in systems where the
star is surrounded by a massive disk. further, if the instability can grow to
moderate amplitude, then the coupling can transport significant amounts of
angular momentum from the star in to the circumstellar disk. We find that,
for the particular case of rotating protostars during the accretion phase, the
time scales can be short enough to remove angular momentum from the central
star at a significant rate.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophysical Journal. }
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{ Pre-Main Sequence Evolution in the Taurus-Auriga Molecular Cloud}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Scott J. Kenyon and Lee Hartmann }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Harvard-Smithsonian Center for Astrophysics, 60 Garden St.,
Cambridge, MA 02138, USA}
%% Within the following brackets you place your text:
{This paper analyzes optical and infrared photometry of
pre-main sequence stars in the Taurus-Auriga molecular cloud.
More than half of the stars in our sample
have excess near-infrared emission.
The near-infrared excesses correlate very well with
other measures of activity, such as H$\alpha$ emission,
ultraviolet excess emission, millimeter continuum emission,
and the presence of reflection nebulae and molecular outflows.
The infrared colors and the ratio of far-infrared to bolometric
luminosity display a smooth progression from the most
deeply embedded protostars to optically visible T Tauri stars.
Infalling envelope models account for the colors of protostars;
simple disk models similarly reproduce the colors of
many T Tauri stars.
Both the stellar birthline and a $10^5$ yr isochrone
provide a reasonable upper envelope to the luminosity
distribution of optically visible stars in the HR diagram.
Only a few stars in the cloud have apparent ages exceeding
2--3 $\times~10^6$ yr, as derived from detailed stellar
evolution calculations.
The distribution of stars in the HR diagram indicates
that the cloud has formed stars at a roughly constant
rate for the past 1--2 $\times~10^6$ yr.
Analyses of the J and K luminosity functions
support this conclusion.
Within the uncertainties, the observed mass distribution
for optically visible stars agrees with a
Miller-Scalo initial mass function.
Source statistics imply a lifetime of
1--2 $\times~10^5$ yr for the typical
protostar in Taurus-Auriga.
There is no evidence, however, that these
sources lie on the stellar birthline.
Indeed, the protostellar luminosity function
is essentially identical to the luminosity function
derived for optically visible T Tauri stars in the cloud.
These results provide some support for the evolutionary
sequence -- embedded protostar $\rightarrow$ T Tauri star
with a circumstellar disk $\rightarrow$ T Tauri star without
a circumstellar disk -- currently envisioned in standard
models of low mass star formation.
Source statistics and infrared color-color diagrams
demonstrate that pre-main sequence stars develop
bluer colors and display less evidence for
circumstellar material with time.
The data show little evidence, however, for
the luminosity evolution expected along
the proposed evolutionary sequence.
Time-dependent accretion during the infall phase may
sizes of circumstellar disks around T Tauri stars.}
% Here you write which journal accepted your paper, for example:
{ Astrophys. J. Suppl., October 1995}
\newpage
%% Between these brackets you write the title of your paper:
%{\large\bf{Title of Paper}}
{\large\bf {Study of Structure and Small Scale Fragmentation in TMC1
}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
%{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
{\bf{W. D. Langer$^1$, T. Velusamy$^1$, T. B. H. Kuiper$^1$, S. Levin$^1$, E. Olsen
$^1$, V.Migenes$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1${Jet Propulsion Laboratory, California Institute of Technology,
MS 169-506, Pasadena, CA 91109, USA}\\
$^2${Australia National Telescope Facility,
CSIRO, PO Box 76, Epping, NSW 2121 Australia}
%$^1$ {European Southern Observatory, Casilla 19001, Santiago 19, Chile} \\
%$^2$ {Cerro Tololo Inter-American Observatory, National Optical Astronomy
% Observatories, Casilla 603, La Serena, Chile} \\
%$^3$ {Las Campanas Observatory, Carnegie Inst. of Washington, Casilla
% 601, La Serena, Chile}
%% Within the following brackets you place your text:
%{This is the abstract of your paper}
{Large scale C$^{18}$O maps show that the Taurus Molecular Cloud 1
(TMC1) has numerous cores located along a ridge which extends about
12' by at least 35'. The cores traced by
C$^{18}$O are about a few arcmin (0.1 - 0.2 pc) in extent, typically contain
about 0.5-3 $M_{\odot}$, and are probably gravitationally bound. We
present a detailed study of the small scale fragmentary structure of
one of these cores, called core D, within TMC1 using very high
spectral and spatial resolution maps of CCS and CS. The CCS lines are
excellent tracers for investigating the density, temperature and
velocity structure in dense cores. The high spectral resolution,
0.008 km s$^{-1}$, data consist mainly of single dish, Nyquist sampled
maps of CCS at 22 GHz with 45$''$ spatial resolution taken with
NASA's 70m DSN antenna at Goldstone. The high spatial resolution
spectral line maps were made with the VLA (9$''$ resolution) at
22 GHz and with the OVRO millimeter array in CCS and CS at 93 GHz and
98 GHz, respectively, with 6$''$ resolution. These maps are
supplemented with single dish observations of CCS and CC$^{34}$S
spectra at 33 GHz using a NASA 34m DSN antenna, CCS 93 GHz, C$^{34}$S
(2-1) and C$^{18}$O (1-0) single dish observations made with the AT\&T
Bell Laboratories 7m antenna.
Our high spectral and spatial CCS and CS maps show that core D is
highly fragmented. The single dish CCS observations map out several
clumps which range in size from $\sim$45$''$ to 90$''$ (0.03
to 0.06 pc). These clumps have very narrow intrinsic linewidths,
0.11 to 0.25 km s$^{-1}$, slightly larger than the thermal line width
for CCS at 10 K, and masses about 0.03 to 0.2 $M_{\odot}$.
Interferometer observations of some of these clumps show that they
have considerable additional internal structure, consisting of several
condensations ranging in size from $\sim$ 10$''$ to 30$''$
(0.007 to 0.021 pc), also with narrow linewidths. The mass of these
smallest fragments is of order 0.01
$M_{\odot}$. These small scale structures traced by CCS appear to
be gravitationally unbound by a large factor. Most of these objects
have masses that fall below those of the putative proto-brown dwarfs
($\leq$ 0.1 $M_{\odot}$). The presence of many small gravitationally
unbound clumps suggests that fragmentation mechanisms other than a
purely Jeans gravitational instability may be important for the
dynamics of these cold dense cores.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophys. J. }
\vspace*{0.3cm}
{\large\bf{Detecting T Tauri disks with optical long-baseline interferometry}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ F. Malbet$^{1,2}$, C. Bertout$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Laboratoire d'Astrophysique, Observatoire de Grenoble,
BP 53, 38041 Grenoble cedex 9, France}\\
$^2$ {Jet Propulsion Laboratory, California Institute of Technology,
Pasadena, CA 91109, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: malbet@gag.observ-gr.fr}
%% Within the following brackets you place your text:
{ We present synthetic images of disks around T Tauri stars. We calculate
visibility curves in order to study the possibility of directly detecting
thermal emission from T Tauri disks. Total fluxes of T Tauri disks are
compared to the sensitivity of {\em VISA}, the interferometric sub-array
of the European {\em Very Large Telescope}. We conclude that thermal
emission from circumstellar disk around T Tauri stars is detectable with
current or soon-to-be interferometric techniques at wavelengths longer
than $2.2\mbox{ $\mu$m}$. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy \& Astrophysics Supplement Series }
\vspace*{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Submillimeter Continuum Observations of the T Tauri
Spectroscopic Binary\\ GW Orionis}}
\def\micron{\hbox{$\mu$m}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Robert D. Mathieu$^1$, Fred C. Adams$^2$, Gary A. Fuller$^3$,
Eric L.N. Jensen$^1$, David W. Koerner$^4$, and Anneila I. Sargent$^5$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter
St., Madison, WI 53706-1582, USA} \\
$^2$ {Department of Physics, University of Michigan, Ann Arbor, MI
48109, USA} \\
$^3$ {National Radio Astronomy Observatory, Tucson, AZ, USA and
Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA} \\
$^4$ {Division of Geological and Planetary Sciences, California Institute
of Technology, Pasadena, CA 91125, USA} \\
$^5$ {Division of Physics, Mathematics, and Astronomy, California Institute
of Technology, Pasadena, CA 91125, USA}
{E-mail contact: mathieu@madraf.astro.wisc.edu}
%% Within the following brackets you place your text:
{ We have measured submillimeter fluxes from the classical T Tauri
spectroscopic binary GW Orionis. Single-dish measurements were
obtained at 350 \micron, 450 \micron, 800 \micron, 850 \micron, and
1100 \micron\ with the James Clerk Maxwell Telescope, and an
interferometric map (beam FWHM of 2.5$^{\prime\prime}$) was obtained at
1360 \micron\ with the Owens Valley millimeter-wave array. The
submillimeter luminosity of GW Ori is comparable to the largest yet
found among T Tauri and Herbig Ae stars. The source is unresolved in
our interferometric map implying that the emitting material is
confined within a radius of 500 AU.
The source of the submillimeter emission must be
circumbinary. In an optically thin, isothermal (150 K) approximation
we place a lower limit of 0.3 $M_\odot$ on the mass of circumbinary
material, with an uncertainty of at least a factor three due to
opacity normalization. The confinement of the submillimeter emission
within $\approx 500$ AU leads us to conclude that the origin of the
submillimeter luminosity is a circumbinary disk. These conclusions are
independent of specific disk models. Using the pure-disk model for GW
Ori of Mathieu {\it et al.} (1991), we find a disk mass of 1.5 $M_\odot$,
again with an uncertainty of at least a factor three.
A disk mass of 1.5 $M_\odot$ is 40\%--50\% of the total stellar
mass. The circumbinary disk would be expected to drive rapid evolution
of both the orbital semi-major axis and eccentricity. The
low-eccentricity orbit of GW Ori is in marked contrast to this
prediction, possibly indicating that the disk surface density in the
vicinity of the binary may be small. The dynamical stability of such a
massive disk is not clear, but stable disks of smaller mass are within
the measurement uncertainty.
We find the observations are well fit with a grain opacity
$\kappa_\nu \propto \nu^\beta$ having an exponent $\beta = 2$ at
submillimeter wavelengths. Somewhat smaller values of $\beta$ would
also be acceptable, but $\beta \approx 1$ does not reproduce the data
well. If a disk mass greater than 1.5 $M_\odot$ is taken to be
unstable and short-lived, then our adopted opacity normalization of
Hildebrand (1983) and Pollack {\it et al.} (1994) is an approximate lower
limit to the true value for the GW Ori disk.
The specific disk-shell model of Mathieu {\it et al.} (1991) cannot
reproduce these submillimeter observations. More generally, the
confinement of at least 0.3 $M_\odot$ within a radius of 500 AU with no
evidence of extension to larger radii is problematic for origin of the
submillimeter emission in an infalling envelope. Furthermore we have
found that a single steady-accretion disk cannot reproduce the
observed spectral energy distribution at both near-infrared and
submillimeter wavelengths; a more luminous circumbinary disk is
required to explain the large submillimeter luminosity.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
\vspace*{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Evidence for ongoing star formation in the Carina nebula}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ S. T. Megeath$^1$, P. Cox$^{1,2}$,
L. Bronfman$^3$, P. R. Roelfsema$^4$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Max--Planck--Institut f\"{u}r Radioastronomie, Postfach 2024,
D--53121 Bonn, Germany} \\
$^2$ {Observatoire de Marseille, 2 pl. Leverrier, F--13248 Marseille
Cedex 4, France} \\
$^3$ {Departamento de Astronomia, Universidad de Chile, Casilla 36-D,
Santiago, Chile} \\
$^4$ {SRON, Postbus 800 AV, Groningen, The Netherlands}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: v701tom@mpifr-bonn.mpg.de}
%% Within the following brackets you place your text:
{
We present the first evidence that star formation is continuing in the
molecular complex associated with the Carina nebula. CO observations
in several isotopomers and transitions reveal a clumpy and dynamically
complex structure in the molecular gas south of the OB association
Trumpler~16. Super--resolution IRAS images of the region show a
1.1~10$^4 $~L$_{\odot}$ point source (IRAS~10430--5931) in a molecular
clump at the edge of the cloud complex. The IRAS colors are
characteristic of deeply embedded young stellar objects. Through a
comparison with a published [SII] photograph, we find that the clump
is a bright--rimmed globule. The mass of the globule is 80
M$_{\odot}$, yielding a luminosity--to--mass ratio of $\sim 100
$~L$_{\odot}$/M$_{\odot}$. $J$, $H$ and $K'$--Band imaging of the
IRAS source shows a group of highly reddened stars and bright
nebulosity. We argue on a statistical basis that some of the reddened
stars must be embedded in the globule and are not background objects.
Additionally, several of the reddened stars exhibit anamolous
near--infrared colors which are typical of embedded pre--main sequence
stars. The near--infrared images show that all apparent star formation
is taking place near the rim, 0.5 pc from the peak in $^{13}$CO(2-1)
emission. This morphology is suggestive of star formation triggered
by radiation driven shocks.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A }
\newpage
%% Between these brackets you write the title of your paper:
{\large\bf{Search for 6 cm Formaldehyde Masers in 22 Galactic Star-Forming Regions}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ David Mehringer$^1$, W. M. Goss$^2$ \ and Patrick Palmer$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {University of Illinois, Department of Astronomy, 1002 W. Green St.,
Urbana, IL 61801, USA} \\
$^2$ {National Radio Astronomy Observatory, Box O, Socorro, NM 87801, USA} \\
$^3$ {University of Chicago, Department of Astronomy \& Astrophysics,
5640 S. Ellis Ave., Chicago, IL 60637, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: dmehring@sirius.astro.uiuc.edu}
%% Within the following brackets you place your text:
{A search for 6 cm H$_2$CO (formaldehyde) masers in 22 Galactic
star-forming
regions has been carried out using the B configuration of the VLA.
These observations have 2$^{\prime\prime}$ angular resolution. The sensitivity
ranges between 2 and 4 mJy beam$^{-1}$. No new H$_2$CO masers are
detected. The paucity of these masers suggests that 1) their lifetimes
are quite short, and/or 2) a narrow range of
physical parameters is necessary for their formation.
The known H$_2$CO maser source NGC 7538 was also observed. The line
flux of one of its two components has tripled over a 15 year
period.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. (20 October, 1995)}
\vspace*{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{What Is Powering the Orion Kleinmann-Low Infrared Nebula?}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Karl M. Menten \ and Mark J. Reid}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
Cambridge, MA 02138, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: menten@cfa.harvard.edu}
%% Within the following brackets you place your text:
{We used the Very Large Array to observe the Orion BN/KL region simultaneously
at frequencies of 8.4 and 43.1 GHz with $0\rlap{.}{''}25$ resolution.
At 8.4 GHz we detect a rich cluster of compact radio continuum sources, some
of which are coincident with infrared sources while others do not have
known infrared counterparts. At 43.1 GHz we observed continuum emission
together with the $v =1, J=1\to0$ SiO maser line, allowing precise
registration of radio continuum relative to SiO emission. We find that
the radio continuum emission from one of the radio sources, I,
coincides with the centroid of the SiO maser distribution.
Our SiO maser maps show intricate velocity structure indicative of
ordered motions that must have a rotating and expanding (or contracting)
component.
Since source I powers an SiO maser it must have a high luminosity, most
likely exceeding $10^4$ $L_{\odot}$.
Precise astrometry shows that it does {\it not}
coincide with the mid-infrared source IRc 2.
Given that the radio emission from source I is not affected by dust
extinction, it locates the central (proto)star powering the IRc 2
complex. This suggests that the location and morphology of the infrared
emission from ``IRc 2'' is determined by inhomogeneities of the
dust envelope surrounding the central star. Furthermore, this brings
into question all previous luminosity estimates of IRc 2 and opens the
possibility that other sources contribute significantly to the energetics
of the Orion-KL region. In particular, we suggest that another infrared
source, $n$, which is coincident with a peculiar double radio source, may be
responsible for at least some of the energetic phenomena observed in the
region.}
% Here you write which journal accepted your paper, for example:
{Accepted by The Astrophysical Journal (Letters)}
\vspace*{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Complex Molecules in Sagittarius B2(N): The Importance of
Grain Chemistry}}
%% Here comes the author(s) of the paper, please indicate within
%% $^...$
%% the number which corresponds to the institute of each author.
{\bf Yanti Miao, David M. Mehringer, Yi-Jehng Kuan, \& Lewis E. Snyder }
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{University of Illinois, Department of Astronomy, 1002 W. Green
St.,
Urbana, IL 61801, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for
%% example:
{E-mail contact: yanti, dmehring@sirius.astro.uiuc.edu}
%% Within the following brackets you place your text:
{The complex molecules vinyl cyanide (CH$_2$CHCN), methyl formate
(HCOOCH$_3$), and ethyl cyanide (CH$_3$CH$_2$CN) were observed in the
Sgr B2 star-forming region with the BIMA millimeter wavelength array.
A region with diameter $$20 arcseconds; for most, the emission is almost unresolved in the E-W
direction. In most cases these filaments have a position angle which is very
close to that measured for the molecular cloud over $>$10 arcminutes. The
NH$_3$ emission line delineates the location of the denser molecular gas. The
presence of dense clouds S and SW of the continuum source and the sharp
fall-off of the HII continuum intensity to the SW gives support to the notion
that the expansion of the HII region is halted by dense neutral gas to the SW.
The structures traced by the (3,3) transition differ greatly from those found
for the (1,1) line. Toward the HII region DR~21, there are several (3,3)
emission maxima, two of which exhibit prominent negative velocity line wings.
The (3,3) line traces the hotter shocked gas. Given the negative velocity
wings, the morphology of the (3,3) line emission and the location of the
NH$_3$ emission relative to the powerful outflow seen in vibrationally excited
H$_2$ and other molecules, we conclude that the NH$_3$ represents the remnant
material which has survived the powerful outflow. We estimate the location of
the outflow source assuming that this is located near the shocked gas midway
between the two NH$_3$ (3,3) maxima with prominent negative velocity line
wings.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap.J., currently scheduled for October 20 issue}
\vspace*{0.5cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Studies of dense molecular cores in regions of massive star
formation. III. Statistics of the core parameters}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ I.~Zinchenko$^{1,2}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute of Applied Physics of the Russian Academy of Sciences,
Uljanov~st.~46, 603600 Nizhny Novgorod, Russia} \\
$^2$ {Helsinki University Observatory, T\"ahtitorninm\"aki, P.O.Box 14,
FIN-00014 University of Helsinki, Finland} \\
E-mail contact: zin@appl.nnov.su
%% Within the following brackets you place your text:
{We analyze further the observational data for dense cores in regions
of high mass star formation (HMSF) obtained recently with the SEST and
Mets\"ahovi radio telescopes. The statistical distributions of the
core sizes, masses, mean densities, CS line widths and CO temperatures
are constructed. To reduce the influence of the selection effects we
consider separately also a subsample which includes the cores located
within 3 kpc from the Sun. The size distribution peaks sharply at its
lower edge ($\sim 1$~pc). The mass spectrum for $M\geq
1000$~M$_\odot$ can be fitted by the power law ($dN/dM \propto
M^{-1.7}$ for the 3~kpc subset).
The galacto-centric dependences of these parameters in the range
$R\approx 7-11$~kpc are investigated. There is a trend to a
systematic decrease of the mean density of the cores with increasing
galacto-centric distance.
We have attempted to investigate the radial dependences of some
physical parameters in several cores which have a simple structure.
The CS line areas drop rather quickly with $r$, corresponding to
$r^{-1.5}$ to $r^{-2}$. The CS line widths decrease towards the core
edges as well, sometimes below the C$^{34}$S line width (measured at
the CS peak position). The ratios of the CS and C$^{34}$S line widths
and intensities are described preferably by the models with density
inhomogeneities in the cores.
We investigate the $L - \Delta V$ and $L - \bar{n}$ relationships for
the CS cores. Although there is a trend for increasing line width with
increasing size the correlation is very weak. There is in general a
higher velocity dispersion in HMSF cores than in CO clouds and dense
cores in dark clouds. We suggest that the $L - \bar{n}$ data imply an
upper limit to the mean density depending on the size. }
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. Astrophys. }
\newpage
\begin{center}
{\Large\em Meetings}
%\end{center}
\vspace*{1cm}
{\bf First Announcement}
\vspace*{0.5cm}
{\LARGE\bf Herbig-Haro Flows and the Birth of Low Mass Stars}
\vspace*{0.5cm}
{\large\bf to be held 20 -- 25 January 1997 in Chamonix, France}
\end{center}
{\bf Scientific Organizing Committee: }
Claude Bertout (France, Co-chair), Karl-Heinz B\"ohm (USA), Nuria
Calvet (Venezuela), Max Camenzind (Germany), John Dyson (England),
Suzan Edwards (USA), George Herbig (USA), Alex Raga (Mexico), Bo
Reipurth (Chile, Co-chair), Luis Felipe Rodriguez (Mexico).
An application for this meeting to have status as an IAU Symposium has
been submitted to the IAU Executive Committee.
\vspace*{0.5cm}
{\bf Symposium Objective:}
The study of low mass star formation processes has undergone an
explosive development in recent years, and is among the fastest
developing subjects of contemporary astrophysics. Herbig-Haro flows,
in addition to being remarkable astrophysical laboratories of their
own right, are now regarded as an essential part of the birth of a
star. With this Symposium, we intend to provide a comprehensive
overview of our present knowledge of Herbig-Haro flows,
observationally as well as theoretically, to explore the latest
results on the earliest stellar evolutionary stages, and to tie the
outflow phenomena from young stars into the general understanding of
how stars form.
\vspace*{0.5cm}
{\bf General topics to be discussed:}
\begin{itemize}
\item{Properties and Physics of Herbig-Haro Flows}
\item{Herbig-Haro Flows and Other PMS Outflow Phenomena}
\item{Formation and Properties of the Driving Sources of HH Jets}
\item{The Physics of Accretion/Ejection Events}
\item{Collapse Models, Binary Formation, and Angular Momentum Loss}
\item{Infalling Envelopes, Circumstellar Disks and Stellar Winds}
\end{itemize}
\vspace*{0.5cm}
Additional information will be presented in the Star Formation
Newsletter as it becomes available. Calls for registration will come
with the Second Announcement. Further inquiries and suggestions should
be addressed to the two chairmen (bertout@gag.observ-gr.fr,
reipurth@eso.org).
\newpage
\begin{center}
{\Large\em New Jobs}
\end{center}
\vspace*{0.6cm}
\begin{center}%
{\Large Postdoctoral Research Assistant
%
{\Large Molecular Line Astronomy}}%
\end{center}
Applications are invited for an astronomer to contribute to an
observational and interpretational based study of the physics
and chemistry of molecular clouds and the Interstellar Medium.
The aims are to study the chemical, physical and dynamic structure
of molecular cloud cores, with emphasis on the physics of photo
dissociation regions and on sites of high-mass star formation.
The current programme includes studies of the physical properties
of neutral and atomic gas in these regions using submillimetre
spectroscopy of molecular lines, interstellar chemistry, molecular
outflow sources, structure and dynamics of high mass star formation
regions, and is supported by time-dependent chemical modelling
of ionisation fronts and clumpy clouds. Other areas of interest
to group members include studies of the central region of the
Galaxy; studies of the chemical abundances of warm dense molecular
cores, especially trying to understand the anomalous molecular
abundances in regions such as the Orion Molecular Cloud and other
regions of high-mass star formation; studies of Bok and Cometary
Globules; studies of the interstellar medium in other galaxies.
There will be a wide range of new programmes starting up following
the launch of ISO, ranging from planetary studies, through star
formation and ISM chemistry, to galaxies. The PDRA will be expected
to play a major r\^{o}le in collecting, analysing and interpreting
the molecular line data, and to work in collaboration with other
academic staff including Prof. Glenn White and Dr Peter Williams,
on the observing, interpretation and modelling parts of the programme.
Applicants must have or be about to obtain a PhD, and should
have observational experience in molecular line astronomy, although
those with related expertise will be considered. Applicants may
be expected to pass a high altitude medical test, suitable for
working at Mauna Kea.
Informal enquiries may be made to Prof. G White, Department of Physics on
0171-975-5056 or by e-mail to G.J.White@qmw.ac.uk. Further details of the
QMW astronomical research programmes are available on the Internet at
world-wide-web URL: http://www.qmw.ac.uk/$\sim$ugap735/Astronomy.html
The appointment, for two and a half years in the first instance, will start
from October 1st 1995, and is funded by a PPARC rolling grant, with a
salary in the range {\it\pounds\/}14,962 - {\it\pounds\/}19,513 pa
inclusive, depending on age and experience.
For further details and an application form please telephone
0171-975-5171 (24 hour answerphone). Completed application forms,
along with the names and addesses of two referees, plus a detailed
curriculum vitae and copies of all publications should be submitted
by 19th June 1995 to the Recruitment Co-ordinator, Personnel
Office, Queen Mary \& Westfield College, Mile End Road, London
E1 4NS.
\newpage
\begin{center}
{\Large\em New Books}
\end{center}
\vspace*{0.3cm}
\begin{center}
{\Large\bf Planetary Systems: Formation, Evolution, and Detection}
{\bf Edited by Bernard F. Burke, J\"urgen H. Rahe and Elizabeth E. Roettger}
\end{center}
These are the proceedings of the First Internation Conference, held in
Pasadena, California on December 8--10, 1992. Reprinted from
Astrophysics and Space Science Volume 212, Nos.1-2, 1994.
Selected articles of particular interest for the star formation
community:
T. Owen: The Search for Other Planets: Clues from the Solar System\\
V.S. Safronov \& E.L. Ruskol: Formation and Evolution of Planets\\
G.W.Wetherill: Possible Consequences of Absence of ``Jupiters'' in
Planetary Systems\\
S. Sasaki: Dust Blobs in the Solar Nebula-Primary Distended
Atmosphere\\
B. Donn \& J.M. Duva: Formation and Properties of Fluffy
Planetesimals\\
R. Neuh\"auser \& J.V. Feitzinger: Radial Migration of Planetesimals\\
S. S. Kumar: Very Low Mass Stars, Black Dwarfs and Planets\\
C.A. Grady et al.: Detection of Accreting Circumstellar Gas around
Weak Emission-Line Herbig Ae/Be Stars\\
M.R P\'erez et al.: The Evidence for Clumpy Accretion in the Herbig Ae
Stars HR 5999\\
P.S. Th\'e \& F.J. Molster: Protoplanetary Dust Clouds in Disks of
Herbig Ae/Be Stars\\
N.J. Evans et al.: Identification of a Collapsing Protostar\\
H. Beust et al.: Cometary-Like Bodies in the Protoplanetary Disk
around $\beta$ Pictoris\\
J. Bouvier et al.: Synthetic Images of Protoplanetary Disks around
Young Stars\\
M. Clampin et al.: New Observations of the $\beta$ Pictoris
Circumstellar Disk with the JHU Adaptice Optics Coronograph\\
R. Ferlet et al.: Inner Part Observation of the $\beta$ Pictoris
Disk\\
A.I Sargent \& S.V.W. Beckwith: The Detection and Study of
Pre-Planetary Disks\\
S. Terebey et al.: Millimeter Continuum Measurements of Circumstellar
Dust around Very Young Low-Mass Stars\\
P.G. Mezger: The Search for Protostars Using Millimeter/Submillimeter
Dust Emission as a Tracer\\
Th. Henning \& E. Thamm: Cold Dust around Chamaeleon Stars\\
C. Friedemann et al.: Cloudy Circumstellar Dust Shells around Young
Variable Stars\\
J.E. Van Vleve et al.: 10-$\mu$m Images and Spectra of T Tauri Stars\\
N. Ohashi et al.: The Nobeyama Millimeter Array Survey for
Protoplanetary Disks around Protostar Candidates and T Tauri Stars in
Taurus
Kluwer Academic Publishers 1994, Hardbound ISBN 0-7923-2895-7\\
Price NLG 380.00/USD 217.00/GBP 148.50\\
Payment by check, money order or credit cards (Access, Eurocard,
Mastercard, American Express, Visa, Diners Club)\\
For customers in USA, Canada and Mexico:\\
Kluwer Academic Publishers, Order Department\\
P.O.Box 358, Accord Station\\
Hingham, Ma 02018-0358, USA\\
Tel. (1) 617-871-6300\\
Fax: (1) 617-871-6528\\
E-mail: kluwer@world.std.com
For the rest of the world:\\
Kluwer Academic Publishers, Order Department\\
P.O.Box 322, 3300 AH Dordrecht\\
The Netherlands\\
Tel. (31) 78-524400\\
Fax: (31) 78-524474\\
E-mail: vanderlinden@wkap.nl
\newpage
\begin{center}
{\Large\em Short Announcements}
\end{center}
\vspace*{0.6cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Five College Astronomy Ph.D. Theses available on WWW}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Karen M. Strom$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Five College Astronomy Dept., University of Massachusetts,
Amherst, MA 01003, USA\\
kstrom@hanksville.phast.umass.edu}
%% Within the following brackets you place your text:
{The Ph.D. theses from the Five College - University of Massachusetts
Astronomy Department are now becoming available over the World Wide Web.
The first thesis available, Herbig Ae/Be Stars: An Investigation of Molecular
Environments and Associated Stellar Populations by Lynne A. Hillenbrand is now
available. Postscript versions of the individual chapters are also available.
Theses will be added as they are accepted by the department.
The URL for the home page of our thesis server is:
http://decoy.phast.umass.edu/}
\vspace*{4cm}
\fboxrule0.02cm
\fboxsep0.4cm
\fbox{\rule[-0.9cm]{0.0cm}{1.8cm}{\parbox{16cm}
{The Star Formation Newsletter is a vehicle for fast distribution of
information of
interest for astronomers working on star formation and molecular
clouds. You can submit material for the following sections: {\em
Abstracts of recently accepted papers} (only for papers sent to refereed
journals, not reviews nor conference notes), {\em Dissertation Abstracts}
(presenting abstracts of new Ph.D dissertations), {\em Meetings}
(announcing meetings broadly of interest to the star formation
and interstellar medium community), {\em New Books} (giving details of
books relevant for the same community), {\em New Jobs} (advertising
jobs specifically aimed towards persons within our specialty), and {\em
Short Announcements} (where you can inform or request information from
the community). \\
{\bf Latex macros for submitting abstracts and dissertation abstracts
are appended to each issue of the newsletter}. \\
The Star Formation Newsletter is available on the World Wide Web.
You can either access it via the ESO Portal
(http://http.hq.eso.org/eso-homepage.html) or directly in two ways: by
issue number
%\linebreak
(http://http.hq.eso.org/star-form-newsl/star-form-list.html) or via a
wais index (wais://http.hq.eso.org:2010/starform).
You can also access it through the University of Massachusetts
Astronomy World Wide Web server, the URL for its home page is http://www-astro.phast.umass.edu/
}}}
\end{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% %%%
%%% LaTeX MACRO FOR THE STAR FORMATION NEWSLETTER %%%
%%% %%%
%%% Please use for abstracts of papers which have been ACCEPTED in %%%
%%% REFEREED JOURNALS (do not send abstracts of reviews for books %%%
%%% or conference notes). Merely fill in the brackets below and %%%
%%% mail to reipurth@eso.org. If you have problems, let me know in %%%
%%% an accompanying note and I will fix them. %%%
%%% %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\documentstyle{article}
%\textwidth 18cm
%\textheight 23cm
%\oddsidemargin -1cm
%\topmargin 0cm
%\parskip 0.15cm
%\parindent 0pt
%\small
%\begin{document}
%% Between these brackets you write the title of your paper:
{\large\bf{Title of Paper}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {European Southern Observatory, Casilla 19001, Santiago 19, Chile} \\
$^2$ {Cerro Tololo Inter-American Observatory, National Optical Astronomy
Observatories, Casilla 603, La Serena, Chile} \\
$^3$ {Las Campanas Observatory, Carnegie Inst. of Washington, Casilla
601, La Serena, Chile}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: reipurth@eso.org}
%% Within the following brackets you place your text:
{This is the abstract of your paper}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%\end{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%
%%% LaTeX MACRO FOR DISSERTATION ABSTRACTS
%%%
%%% Please use the following macro for your thesis abstract. You
%%% have one full page for everything, and you are very welcome to
%%% go into detail with your results, so the readers get a
%%% comprehensive overview of your work. Merely fill in the
%%% brackets below and mail to reipurth@eso.org.
%%%
%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% To process with latex, first remove the % in front of latex commands
%\documentstyle{article}
%\textwidth 18cm
%\textheight 23cm
%\oddsidemargin -1cm
%\topmargin 0cm
%\parskip 0.15cm
%\parindent 0pt
%\small
%\begin{document}
\begin{center}
%% Between these brackets you write the title of your thesis:
{\Large\bf{Title of Thesis}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{ Author }}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Steward Observatory, University of Arizona, USA}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: European Southern Observatory, Casilla 19001,
Santiago 19, Chile}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 1994: }
%% Here comes your e-mail address:
{Electronic mail: doctor@sun.institute.edu}
%% Name of your adviser:
{Ph.D dissertation directed by: Galileo Galilei}
%% Month and Year of thesis:
{Ph.D degree awarded: Month Year}
\vspace*{0.8cm}
\end{center}
%% Within the following brackets you place your text:
{This is the abstract of your thesis}
%\end{document}